Electric plug



W. HUPPERT ELECTRIC PLUG April 19, 1932.

Filed March 16, 1929 INVENTOR Vse 'Patented Apr. 19,1932

PATENT OFFICE WILLIAM normar, or NEW YORK, N. Y.

ELECTRIC PLUG vApplication led March 16, 1929. Serial No. 347,721.

My invention relates to electric fittings of the screw plug type,including in some cases a.thermoiasher contained in the plug. i

One principal object. of the invention is to t .C provide a plugstructure which is very simple,

and arranged for easy and rapid assembly.r

Another object is to provide a thermo-flasher which -isassembled as aunit with an insulator which alsol carries the center contact of theplug and is inserted and secured in the plug shell in a simple andeffective way.

The characteristics and advantages of the rinvention are furthersufficiently explained in connection with the following detaildescriptionv of the accompanying drawings, which illustrate certainrepresentative embodiments of the invention. After considering theseexamples, skilled persons will understand that many variations may bemade without departing from the principles involved, and I contemplatethe employment of any structures that are properly within the scope ofthe appended claims.

Fig. 1 is an axial section of a'plug structure embodying the inventionin one form;

Fig. 2 is a top plan; Fig. 3 is a section at 3-3 of Fig. 1; and Fig. 4is a right-side elevation of the insulator and thermo-flasher assembledas a unity and ready for insertion in the plug shell. Disregardingthethermo-lasher, described hereinafter, the plug comprises a threadedshell l which may be as usual except for its structure or formation atthe upper end (as viewed in Fig. l). At the upper end the sheet metalcomposing the shell is turned in as at 2 and cut to form a polygonal, orpreferably a substantiallyiV square aperture 3, with a plurality (in thepresent example, three) insulator-retaining lingers 4 projecting fromthe aperture-margin. When the shell is ready. to receive the insulatorpresently described, the retaining fingers extend straight up in linewith the lower portions thereof, as shown in dotted lines in Fig. 1.

To co-operate with the shellI provide an insulator 6 of any suitablemoldable composition. lThis has at'its lower or inner end a polygonalformation 71 to correspond with the aperture 3 in the shell; that is, inthe present case the formation 7 of the insulator is substantiallysquare to enter and be held against rotation by the shell apertureformation. Above the inserted portion 7 is a flange 8 resting on theshell flange 2. This flange or outer portion of the insulator may havealmost any form but conveniently it is polygonal, providing fiatperipheral faces above which are formed, on the upper or outer face ofthe insulator, axially directed sockets 9 set inward from shoulders orflanges 10. The insulator is centrally apertured, and any4 suitablemetal center contact member such as 11 is inserted in the aperture andthis may'in turn be connected to any other device, the circuit of whichis to be completed by contact with the shell 1, such for example, as amember of the thermo-asher later described.

The insulator is inserted in the shell in a manner easily understoodfrom the drawings, and is secured by bending the end portions of theretaining fingers 4 over the flanges 10 and down into the socketformations 9, thereby firmly retaining the insulator in position by verysimple means.

In one form the plug structure includes a thermo-flasher 12, assembledas a unit with the insulator and its centercontact, and quickly andeasily inserted in the shell structure, the assembly being completed bythe act of clenching the lingers 4 and one other operation performed ona part of the thermoflasher, as later explained. The thermoflasherplug-provides a simple and economical means for inserting a thermoasherin any desired circuit, such, for example, as that of a lamp, byscrewing one portion of the plug into any screw socket and then screwingthe lamp into the outer or socket portion of the plug structure, as willappear.

When a thermo-flasher is included the shell 1 is extended to provide anouter threaded portion 13, which is dimensioned to act as a socket, toreceive any standard lamp or screw plug. An insulating disk 14 issecured within the metal sleeve at a point intermediate thethreadedportions 1 and 13 or at the bottonil (inward end) of the socketportion 13. Disk 14 must be of smaller diameter than the interior lofthe lower shell portion in order to permit insertion and it is retainedin position y an impressed annular bead l5 in the shell against whichone side of the dished edge rests and impressed lug formations 16engaging the opposite side of the disk edge at three or more spacedpoints around its periphery. The disk has a slot 17, near one edge, forpurposes to be explained.

The thermo-flasher 12 may be of any suitable type. In the presentexample it includes as a principal feature a conducting and contactstrip 20 of fairly stiff, but bendable, spring metal. This has a baseportion 21 apertured to fit around the center Contact 11 which may be inthe form of a solid or a hollow rivet, and may be definitely located andspaced by an insulating washer 22. For securing the parts of thethermo-flasher to the insulator 6, the center contact 11 is preferablyin the form of a hollow rivet, to provide for ventilation and cooling.The strip 20 also has an end portion 23 of reduced width, to passthrough slot 17 in disk 14, and this end portion remains straight, asshown in Fig. 4 and in dotted lines in Fig. 1, after assembly of theinsulator and thermo-asher and until the thermo-flasher is inserted inthe plug structure, after which the portion 23 of strip 2O is bent upangularly, adjacent disk 14, as shown in solid lines in Fig. l, to formthe center contact of the socket portion of the plug structure. Themovable or thermal element 25 of the flasher consists of duplex metal asusual in such devices. It has a portion 26 insulated from the base ofstrip 2O and apertured to receive the center contacts, and in electricalcontact therewith. The parts of the thermo-flasher are secured to theinsulator 6 by the clenching of the tubular rivet. The thermal strip 25has insulated thereon the heating winding 27, one end of which iselectrically connected to the thermal strip at 28 and the other end isconnected to strip 2O at 29. The respective strips carry contacts 30 formaking and breaking the heating circuit. The operation of such devicesis well understood in the art.

The socket portion, 13, of the shell may be inserted in a protectingsleeve 40 of fibre or other suitable insulating material, which may havea tight friction fit on the shell, or-,be otherwise secured thereto.

The complete unit, consisting of the insulator 6 and the thermo-flasher,is inserted in the socket structure and secured by the clenching offingers 4 and bending of part 23 of strip 2O as aboveexplained.

1. An electric socket plug structure comprising a threaded shellprovided with a non-circular aperture at its inner end, the material ofthe shell laterally of the aperture extending beyond the edge of theaperture, retaining fingers projecting from said shell adjacent to saidaperture, an insulator body comprising a portion conforming generally tothe contour of said aperture, and adapted to be received therein, saidinsulator body further comprising portions extending laterally of saidfirst named portion and adapted to abut that part of the shell laterallydisposed to said aperture when said first named portion is positionedwithin said aperture, said insulator body being provided with recesseson a face opposite said first named portion, said recesses being adaptedto receive said retaining fingers when they are bent, a center Contactpassing through said insulator body disposed within said threaded shelland provided with a perforation, the outer end portion of said threadedshell forniing one terminal of the socket Ian insulating disk disposedin said outer end portion of said shell and a conducting strip securedto said center contact adjacent said first named portion of saidinsulator body and disposed and having a length to pass through anaperture in said insulating disk to allow the free end thereof to bebent over the outer face of said insulating disk to serve as the centercontact of the socket of the plug.

2. An electric socket plug structure coniprising a threaded shellprovided with an aperture at its inner end, the material of the shelllaterally of the aperture extending beyond theedge of the aperture,retaining fingers projecting from said shell adjacent to said aperture,an insulator body comprising a portion adapted to be received withinsaid aperture, said insulator body further comprising portions extendinlaterally of said first named portion and a apted to abut that part ofthe shell laterally disposed to vsaid aperture when said first namedportion is positioned within said aperture, said insulator body beingprovided with recesses on a face opposite said first named portion, saidrecesses being adapted to receive saidretaining fingers when they arebent, a center contact passing through said insulator body, disposedwithin said threaded shell, the outer end portion of said threaded shellforming one terminal of the socket, an insulating disk disposed in saidshell, and a conducting strip secured to said center contact adjacentsaid first named portion of said insulator body and disposed and havinga length to pass through an aperture in said insulating disk to allowthe free end thereof to be bent over the outer face of said insulatingdisk to serve as the center contact of the socket of the plug.

3. An electric socket plug structure comprising a threaded shellprovided with a polygonal aperture at its inner end, the niaterial ofthe shell laterally of the aperture extending beyond the edge of theaperture, retaining fingers projecting from said shell adjacent to saidaperture, an insulator body comprising a polygonal portion conforminggenerally to the contour of said aperture,

, contact in the form of a hollow member passing through said insulatorbody, the outer end portion of said threaded shell forming one terminalof the socket, an insulating disk disposed in said shell to form twoseparate compartments therein, and a conducting strip secure'l to saidcenter contact adjacent said first named portion of said insulator bodyand disposed and having a length to pass through a perforation in saidinsulating disk to allow the free end thereof to be bent over the outerface of said insulating disk to serve as the center contact of thesocket of the plug.

4. A combined socket plug and thermo flasher comprising a threaded shellprovided with a non-circular aperture at its inner end, the material ofthe shell laterally of the aperture extending beyond the edge of theaperture, retaining lingers projecting from said shell adjacent to saidaperture, an insulator .body comprising a portion conforming generallyto the contour of said aperture, 'and adapted to be received therein,said insulator body further comprising portions extending laterally ofsaid first named portion and adapted to abut that part of th'e shelllaterally disposed to said aperture When said first named portion ispositioned within said aperature, said insulator body being providedwith recesses on aface opposite said first named portion,="said recessesbeing adapted to receive said retaining fingers when they are bent, acenter contact passing through said insulator body disposed within saidthreaded shell and provided with a perforation, the outer end portion ofsaid threaded shell forming one terminal of the socket, an insulatingdisk disposed in said shell, a conducting strip secured to said centercontact adjacent said first named portion of said insulator body anddisposed andhavingalength to pass through an aperture in said insulatingdisk toallow the free end thereof to be bent over the outer face of saidinsulating disk to serve as the center contact of the socket of theplug, and a thermo-flasher assembled on the inner end of said insulatorbody and comprising a bendable spring metal element secured to the underside of said insulator body by said center contact and adapted tocooperate with said conducting strip to make and break the circuit.

' 5. A combined socket plug and thermo flasher comprising a threadedshell provided with an aperture at its inner end, the material of theshell laterally of the aperture extending beyond the edge of theaperture, retaining fingers projecting from said shell adjacent to saidaperture, an insulator body comprising a portion adapted to be receivedWithin said aperture, said insulator body further comprising portionsextending laterally of said first named portion and ada ted to abut thatpart of the .shell laterally disposed to said aperture when said firstnamed portion is positioned within said aperture, said insulator bodybeing provided with recesses on a face opposite said first namedportion, said recesses being adapted to receive said retaining fingerswhen they are bent, a center contact passing through said insulator bodydisposed within said threaded shell, the outer end portion of saidthreaded shell forming one terminal of the socket, an insulating diskdisposed in said shell, a conducting strip secured to said centercontact adjacent said first named portion of said insulator body anddisposed and having a length to pass through an aperture in saidinsulating disk to allow the free end thereof to be bent over the outerface of said insulating disk to serve as the center Contact of thesocket of the lug, and a thermo flasher assembled on the mner end ofsaid insulating body and comprising a bendable spring metal elementsecured to the under side of said insulator body by said center contactand adapted to cooperate with said conducting strip to make and breakthe circuit.

In testimony whereof I have signed this specification this 8th day ofMarch, 1929. WILLIAM HUPPERT.

